The natural ligands for CCR5 include chemokines (small chemoattractant cytokines) involved in innate immunity, which are natural suppressors of HIV-1 infection (14–17): macrophage inflammatory proteins CCL3 (MIP-1 α) and CCL4 (MIP-1 β), CCL5 (RANTES - regulated on activation, normal T-cell expressed and secreted) and CCL3L1, the most potent among the agonists of CCR5 and HIV-1-suppressant (18). Here, CCR5 is linked to HIV-1 infection.